Theoretical simulation of oxygen transport to brain by networks of microvessels: Effects of oxygen supply and demand on tissue hypoxia

被引:85
作者
Secomb, TW [1 ]
Hsu, R
Beamer, NB
Couli, BM
机构
[1] Univ Arizona, Dept Physiol, Tucson, AZ 85724 USA
[2] Univ Arizona, Dept Neurol, Tucson, AZ 85724 USA
关键词
capillar network; oxygen consumption; oxygen supply; stroke; theoretical model; tissue hypoxia;
D O I
10.1038/sj.mn.7300114
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Objective: Simulations of oxygen delivery by a three-dimensional network of microvessels in rat cerebral cortex were used to examine how the distribution of partial pressure of oxygen (Po-2) in tissue depends on blood flow and oxygen consumption rates. Methods: Network geometry was deduced from previously published scanning electron micrographs of corrosion casts. A nonlinear least-squares method, using images obtained at three different angles, was used to estimate vessel locations. The network consisted of 50 segments in a region 140 mu m x 150 mu m x 160 mu m. A Green's function method was used to predict the Po-2 distribution. Effects of varying perfusion and consumption were examined, relative to a control state with consumption 10 cm(3)O(2)/100 g per min and perfusion 160 cm(3)/100 g per min. Results: In the control state, minimum tissue Po-2 was 7 mm Hg. A Krogh-type model with the same density of vessels, but with uniform spacing, predicted a minimum tissue Po-2 of 23 mm Hg. For perfusion below 60% of control, tissue hypoxia (Po-2 <1 mm Hg) was predicted. When perfusion was reduced by 75%, the resulting hypoxia could be eliminated by a 31% reduction in oxygen consumption rate. Conclusions: The simulations suggest that tissue hypoxia resulting from a severe decrease in brain perfusion, as can occur in stroke, may be avoided by a moderate decrease in oxygen consumption rate.
引用
收藏
页码:237 / 247
页数:11
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